Stereotype Aspects of Undocumented Immigrants Majority of undocumented immigrants in United States come from Mexico as well as across the border. Actually, a study carried out by Pew Hispanic Research Center indicated that undocumented immigrants from Mexico have reduced. For instance, in 2007 there were approximately 7 million immigrants living in America. In 2010, the number declined further to 6.5 million representing 58% of the total population in United States. The decline may be due to several aspects such as increased border enforcement, an increase in deportation, destabilized American job and construction sectors, increasing risks related to the illicit border crossing and wider Mexican economic issues (Borjas, Grogger, and Gordon, 255-282).